An Interactive Annotated World Bibliography of Printed and Digital Works in the History of Medicine and the Life Sciences from Circa 2000 BCE to 2022 by Fielding H. Garrison (1870-1935), Leslie T. Morton (1907-2004), and Jeremy M. Norman (1945- ) Traditionally Known as “Garrison-Morton”

15961 entries, 13944 authors and 1935 subjects. Updated: April 29, 2024

HSU, T. C.

1 entries
  • 13941

Mammalian chromosomes in vitro I: The karyotype of man.

J. Hered., 43, 167-172, 1952.

Since the turn of the twentieth century, chromosomes prepared on microscope slides formed clumps that made it extremely difficult to distinguish them. Although the preparations made the identification of individual chromosomes difficult, by the 1920s cytologists consistently reported a diploid number of 48 human chromosomes. In April 1952, Hsu discovered a technique—the hypotonic solution—that separated the clumped chromosomes, allowing him to observe each one individually. Even though he now could distinguish human chromosomes to a much greater degree than his predecessors, Hsu still reported a diploid number of 48 human chromosomes (see Figure 14 in his 1952 paper). The correct diploid chromosome number of 46 human chromosomes was first reported three years later by Joe Hin Tjio and Albert Levan.

See Hsu, T. C. Human and mammalian cytogenetics: An historical perspective (1979). See also Kottler, Malcolm Jay, "From 48 to 46: Cytological technique, preconception, and the counting of human chromosomes," Bull. Hist. Med., 48 (1974) 465-502.

Subjects: BIOLOGY › Cell Biology, GENETICS / HEREDITY